Weird coolant leak.....thoughts??
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Joined: Oct 2000
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From: From San Diego to Bentonville, AR.....WTF was I thinking?!? Oh yeah, that free state thingy!
St. Jude Donor '15-'16
Weird coolant leak.....thoughts??
I have a slight coolant leak that is unlike anything I have seen before. Doesn't leak when I drive around or after I have parked the car while the engine is still hot. But once the engine cools (about 2 hours later) I have enough drips to leave a pool about 12 inches in diameter. At this slow rate, I have to add coolant about once a month.
I can feel the coolant on the bottom side of the thermostat housing where it connects to the water pump. I replaced the thermostat seal, but to no avail. Don't feel any coolant under the pulley water pump hub, but maybe it's coming from further back on the pump and running down to the thermostat housing.
But if it were the water pump, I would think it would leak while hot and running, not after it cooled off. It's been this way for about three months.
Anybody experience anything like this.....or have some ideas to chase?? Or is it most likely the water pump and leaking this way (which would be a new way to me).
Thanks in advance for any help or thoughts.
Brad
I can feel the coolant on the bottom side of the thermostat housing where it connects to the water pump. I replaced the thermostat seal, but to no avail. Don't feel any coolant under the pulley water pump hub, but maybe it's coming from further back on the pump and running down to the thermostat housing.
But if it were the water pump, I would think it would leak while hot and running, not after it cooled off. It's been this way for about three months.
Anybody experience anything like this.....or have some ideas to chase?? Or is it most likely the water pump and leaking this way (which would be a new way to me).
Thanks in advance for any help or thoughts.
Brad
Last edited by BradSW; May 10, 2009 at 04:45 PM.
Tech Contributor
Joined: May 2008
Posts: 2,843
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Sounds like water pump bearing/shaft wear so that it leaks out slowly now. It will get worse. The highest pressure in the radiator will be when the engine is hot and not running. The engine is a large heat sink with nothing to remove that pent up heat. Hence the system will build pressure up to the limit of the cap. That may be just sufficient to push a little coolant out between the shaft and bearing on the water pump.
I agree you most likely will need to replace the water pump. The water pump is a centrifugal type and while rotating have a lower pressure at the center area and highest at the outer diameter of the pump impeller. This can reduce the pressure the shaft seal sees while the engine is running, even when hot. Once the engine is shutdown, the shaft seal sees the full system pressure. It will leak until it cools down enough to reduce the system pressure down to something that the seal no longer leaks.
